Aluminum electrolysis in non-aqueous monomeric organic acid

Abstract

The invention is directed to the electrochemical treatment of aluminum substrates in a non-aqueous solution of a polybasic organic acid to provide a surface complex which promotes the adhesion of subsequently applied coatings to said surface.

What is claimed is: 
     
       1. A process for treating an aluminum containing sheet substrate which comprises electrolyzing said substrate as an anode in a non-aqueous electrolytic solution comprising a solvent having a dipole moment of at least 1.5 and a compatible monomeric polybasic organic acid, wherein said electrolysis is conducted at a voltage of from about 5 to about 120 volts, with a charge application of from about 1 to about 150 coulombs per square decimeter of substrate, in an electrolyte maintained at a temperature of from about -5° to about 60° C., with a cathode to anode distance of from about 1 to about 25 centimeters. 
     
     
       2. The process of claim 1 wherein said solvent comprises one or more compounds selected from the group consisting of formamide, dimethyl sulfoxide, aniline, dimethyl formamide, mono-, di-, and tri-ethanol amine, and tetrahydrofuran. 
     
     
       3. The process of claim 1 wherein said monomeric, polybasic organic acid comprises one or more acids selected from the group consisting of sulfonic acids, phosphoric acids, carboxylic acids which are at least tribasic and phosphonic acids. 
     
     
       4. The process of claim 3 wherein said sulfonic acids are selected from the group consisting of tridecyl benzene sulfonic acid; dinonyl naphthalene disulfonic acid; 2,2'-stilbene disulfonic acid; dodecyl naphthalene disulfonic acid; di-n-butyl naphthalene disulfonic acid. 
     
     
       5. The process of claim 3 wherein said carboxylic acids are selected from the group consisting of nitrilo triacetic acid; 1,2,4,5-benzene tetracarboxylic acid; alginic acid; diethylene triamine penta-acetic acid; ethylendiamine tetra-acetic acid; and hydroxyethyl ethylene diamine triacetic acid. 
     
     
       6. The process of claim 3 wherein said phosphoric acids are selected from the group consisting of phytic acid; dodecyl-polyoxy ethylene phosphoric acid; and 2-ethylhexyl polyphosphoric acid. 
     
     
       7. The process of claim 1 wherein the concentration of the acid in the electrolyte ranges from about 0.1% by weight to the saturation point. 
     
     
       8. The sheet produced according to the method of claims 1, 2, 3, 4, 5, 6, 7. 
     
     
       9. A photographic element which comprises a light sensitive composition adhered to the substrate prepared according to the process of claim 1. 
     
     
       10. A photographic element which comprises a hydrophilizing composition adhered to the substrate prepared according to the process of claim 1 and a light sensitive composition adhered to said hydrophilizing composition.